Container



July 14, 1964 W E TAYLOR 3,140,808

CONTAINER Filed June 10, 1965 BY @LLM/@Mm United States Patent Office@,lliii Patented July 14, 1954 3,140,808 CONTAINER William EdwardTaylor, Fairfield, Conn., assigner to American Can Company, New York,N.Y., a corporation of New Jersey Filed June 10, 1963, Ser. No. 286,7379 Claims. (Cl. 229-45) This invention relates to easy open libre-bodiedcontainers wherein the opening is effected by tearing open a glued laptype side seam, and has particular reference to a container body whereinthe adhesively secured surfaces of the lap seam area are covered withfilms having varying, predetermined rupturing characteristics topositively ldirect the tear into the fibres of the side seam underlaplayer to thus insure that the tear ends cleanly at the side seamunderlap edge without objectionable onion-skinning.

It is very desirable, from an economical and functional standpoint, topackage products such as cakes of biscuit dough, frozen foods or thelike, in easy open composite containers which include a tubular fibrebody having metal end closures permanently secured thereto. In onecontainer of this type, the side seam edges of the fibre body are joinedin an adhesively secured lap side seam. In order to facilitate openingof the container, a flap or tab is provided at the terminal end of theoverlap layer of the side seam. This tab extends along the entire lengthof the seam on the outside of the body so that it may be readily grippedand pulled to tear open the container at the seam.

In order to prevent inadvertant, premature opening of this type of seam,a relatively strong adhesive is used to provide the seam bond. Thus,when the tabs are pulled outwardly to break open the seam to open thecontainers, the tearing action does not take place in the adhesivelayer. Instead, the tear is randomly directed into either the underlapor overlap of the lap seam. When it is directed into the underlap, itends cleanly at the terminal edge of the underlap, and a satisfactoryopening condi tion is obtained. However, when it is directed into theoverlap, the tear extends past this terminal underlap edge and resultsin a partial delamination of the main body wall. This condition is knownin the trade as onion- Skinning, and is undesirable, since it isunsightly, and results in an unsatisfactory opening operation.

The present invention contemplates the elimination of onion-Skinning bythe utilization of body coatings or laminations having different tearingstrengths, the weaker coating being disposed immediately inwardly of theside seam adhesive and the stronger coating being disposed immediatelyoutwardly of the adhesive. As a result, the weaker coating ruptures whenthe pull tab is pulled, and the tear is consistently directed into theside seam underlap layer, thus insuring the complete elimination ofonion-Skinning.

An object of the invention, therefore is the provision of an easy-openlap seam fibre body wherein coating films having different tearingstrengths are utilized to direct the tear into the lap seam underlaplayer.

Another object is the provision of such a fibre container body which ismade from a blank which has these coating films pre-applied so that onlythe conventional seam forming operations are required when the blank isformed into the body.

A further object of the invention is the provision of such a bodyconstruction wherein the differences in the tearing strengths of theprotective films is effected by varying the thicknesses of the film, byutilizing films having different tensile strengths, or by a combinationof both.

Numerous other objects and advantages of the invention will be apparentas it is better understood from the following description, which, takenin connection with the accompanying drawings, Vdiscloses a preferredembodiment thereof.

Referring to the drawings:

FIGURE 1 is a perspective View of a sealed composite container embodyingthe instant invention;

FIG. 2 is a plan view of a flat blank from which the body of thecontainer illustrated in FIG. l is made, a central portion of the blankbeing broken away;

FIG. 3 is an enlarged fragmentary sectional view taken through the sideseam of the container, the view being taken along a plane indicataed bythe lines 3--3 in FIG. 1; and

FIG. 4 is a view similar to PEG. 3 showing how the tear is directed intothe side seam underlap when the opening flap is pulled to open thecontainer.

As a preferred and exemplary embodiment of the instant invention thedrawings illustrate a composite container C which comprises a tubularlibre body 10 formed of one or more layers 11 of fibrous stock andhaving sheet metal top and bottom closure members 12 formed from tinplate, aluminum or the like material which are secured to the body 10 insuitable end seams 13.

The fibre body 10 preferably is made from a one-piece flat blank 14(FIG. 2) bent into tubular shape to produce a cylindrical body with itsopposing marginal edge portions secured together by a suitable adhesive15 (FIGS. 3 and 4) to produce a lap side seam 16 having an underlap 17and overlap 18.

Prior to its being formed into the body 10, the flat blank 14 isprotected on its inner and outer wall surfaces by suitable films 23, 24of protective coating material to produce a body which is gasproof,moistureproof and greaseproof. In the illustrated form of the invention,the films 23, 24 are shown as being formed of aluminum alloy foil whichis prelaminated to the bre body stock 11 in the usual manner, beingpreferably adhered thereto by a suitable adhesive (not shown). The outerfilm 24 may be suitably imprinted to form a label layer, while the innerfilm 23 forms a lining for the body 1t) which prevents leakage of itscontents. If desired, the inner raw edge of the underlap 17 may becoated with a suitable wax, etc. (not shown) to shield the brous bodystock edge from the container contents.

As clearly seen in FIG. 4, the films 23, 24 extend into the lap sideseam 16 and are disposed on opposite sides of and adhered to theadhesive layer 15, the film 24 forming the outer face of the underlap 17and the film 23 forming the inner face of the overlap 18. To permit easyopening of the container, it is provided with a pull tab 26 which isformed integral with and forms an extension of the overlap 18 and with apair of circumferential lines of weakening 27, 28, such as score lines(see FIGS. l and 2) which extend from the side seam 16 almost completelyaround the body. The tab 26 preferably extends for substantially thefull length of the side seam 16, so that when it is grasped and pulledradially outwardly, the side seam 16 is torn open and the bodythereafter torn along the score lines 27, 23 to expose the contents (notshown).

In order to provide a strong side seam 16, the adhesive which forms thelayer 15 is preferably selected so that it and the bonds which it formswith the lilms 23, 24 are stronger than the adjacent portions of the lapseam 16. As a result, the tear which results when the flap 26 is pulleddoes not take place in the adhesive layer 15, nor does it result inrupture of the bond between the films 23, 24 and the adhesive layer 15.Instead, the container is constructed to direct the tear into the fibrestock 11 of the underlap 17 so that the tear ends cleanly at theunderlap edge 29, thus eliminating any possibility of onion-skinning,which would occur if the tear were directed into the iibre stock of theoverlap 18.

In order to insure that the tear is thus directed into the underlap 17,the container is Constructed so that the pro tective film 24, whichforms the outer layer of the underlap 17, is weaker and less resistantto rupture or tearing than is the protective film 23, which forms theinner layer of the overlap 18. Thus, when the flap is pulled, the film24, being the weakest layer subjected to the pulling force, is the seamcomponent which ruptures. The resultant rupture 27 occurs at the edge ofthe adhesive layer 15, adjacent the juncture of the fiap 26 and theoverlap 18, as best seen in FIG. 4. As a result, the tearing actionextends through the film 24 and into the fibre stock of the underlap 17and thence circumferentially through the latter, asl seen in FIG. 4,until4 it reaches the underlap edge 29 Where it terminates cleanly.

In the instant container, the films 23, 24 are both formed of the samemetallic foil, such as aluminum or aluminum alloy so that both have thesame tensile strength. In order to insure that the film 24 rupturesduring the opening operation, it is made thinner than the film 23 sothat its resistance to tearing is less. In one suggested construction,the film 23 is made .0006 inch in thickness, while the film 24 is made.0003 inch thick. It will be understood that other methods may be usedto provide a film 24 of lesser strength than the film 23. Thus, each ofthese films may be made of a different aluminum alloy which differ intensile strength, the film 23 of course having the greater strength. Insuch event, the lm 24 may be of the same or lesser thickness than thefilm 23.

It Will also be realized that the invention is not limited to the use ofmetal foils for both the films 23, 24. If desired these films may beformed of suitable plastics, such as nylon, mylar, polyethylene,copolymers of vinyl chloride and vinyl acetate, etc., which may eitherbe prelaminated to the fibre stock v11 as integral layers, as by acasting or extrusion process, or may be sprayed, roller coated, orotherwise deposited thereon, either with or without a solvent base, asrequired. As with the metallic foils, the dsired tearing characteristicsof the films 23,24 may be obtained by varying the thicknesses of thesefilms, by using lms having different tensile strengths, or by acombination of these properties, consideration also being given to theproperties (such as water, grease and moisture proofness) necessary tothe effective functioning of the films 23, 24 as container liners andlabels. Generally speaking, when different materials are used, theplastics having the higher tensile strengths, such as mylar, will beparticularly appropriate for the film 23, while the weaker films, suchas polyethylene, are particularly appropriate for use as the film 24. Itwill also be realized that a construction where one film is plastic andthe other a metallic foil will also provide a satisfactory combination,provided the film 24 be substantially less resistant to rupture than thefilm 23. In one such suggested combination, the film 24 comprises analuminum or aluminum alloy foil label, while the liner film 24 comprisesa tough plastic such as mylar or nylon.

It is thought that the invention and many of its attendant advantageswill be understood from the foregoing description and it will beapparent that various changes may be made in the form, construction, andarrangement of the parts without departing from the spirit and scope ofthe invention or sacrificing all of its material advantages, the formhereinbefore described being merely a preferred embodiment thereof.

I claim:

1. A container comprising a tubular fibre body having an inside coatingand an outside coating and having opposed marginal edge portions thereofoverlapped and secured together to provide a lap side seam having anunderlap and an overlap, and a pull tab extending from the overlap ofsaid seam to facilitate opening the container, said inside coating beingmore resistant to rupture than said outside coating for producing abreak in the outside coating on the underlap of said lap side seam andfor directing the tear into the fibre stock of the underlap of the sideseam following the break in said outside coating when said container isopened.

2. A container of the character defined in claim 1 wherein said insidecoating and said outside coating are of different materials havingsubstantially the same thickness.

3. A container of the character defined in claim 1 wherein said insidecoating and said outside coating are of the same material havingdifferent thickness.

4. A container of the character defined in claim 1 wherein said insidecoating and said outside coating are of different materials havingdifferent thickness.

5. A container comprising a tubular fibre body having an inside coatingof a moisture impervious material and Van outside coating of a moistureimpervious material,

said body having opposed marginal edge portions overlapped as an innerlap and an outer lap and adhesively secured together to provide a lapside seam, and a pull tab extending from said outer lap of said seam forpulling said laps apart to open said container, said inside coatingmaterial and said outside coating material having different tensilestrengths and tear characteristics for controlling and confining a breakin a predetermined coating material on one of said laps of said sideseam and a tear in the fibre body covered by said predetermined coatingmaterial when said container is opened.

6. A container of the character defined in claim 5 wherein said insideand said outside coating materials are plastic films.

7. A container of the character defined in claim 6 wherein one of saidcoating materials is a plastic film and the other is a metallic film.

8. A container of the character defined in claim 5 wherein said insideand said outside coating materials are metallic films.

9. A container comprising a tubular fibre body having an inner layer ofaluminum foil secured to the interior wall surface of said body and anouter layer of aluminum foil secured to the exterior wall surface ofsaid body, said body having opposed marginal edge portions disposed inoverlapping relation with the layers of aluminum foil therebetween as aninner lap and an outer lap and adhesively secured together to provide alap side seam, and a pull tab extending from said outer lap of said Seamto open said container, said inner layer of aluminum foil having agreater thickness and strength than said outer layer of aluminum foil sothat when said laps are pulled apart to open said container the outsidelayer of foil on Vsaid inner lap having the thinner and weaker layerwill break first and will adhere to and be completely torn away with theouter lap as the fibrous material in the inner lap of said body isdelaminated toward its terminal edge.

References Cited in the file of this patent UNITED STATES PATENTSl2,814,428 Magill Nov. 26, 1957

1. A CONTAINER COMPRISING A TUBULAR FIBRE BODY HAVING AN INSIDE COATINGAND AN OUTSIDE COATING AND HAVING OPPOSED MARGINAL EDGE PORTIONS THEREOFOVERLAPPED AND SECURED TOGETHER TO PROVIDE A LAP SIDE SEAM HAVING ANUNDERLAP AND AN OVERLAP, AND A PULL TAB EXTENDING FROM THE OVERLAP OFSAID SEAM TO FACILITATE OPENING THE CONTAINER, SAID INSIDE COATING BEINGMORE RESISTANT TO RUPTURE THAN SAID OUTSIDE COATING FOR PRODUCING ABREAK IN THE